Ok so i more and more frequently have people coming to me to get larger things printed than my printer can handle so im thinking of designing a large printer. What are a few things to keep in mind while designing? Which axis should the print head move? Should the platform be the x or y axis or is it more stable as the z?
How large of a printer are you talking about? The primary issue that I know of is making sure the axii are straight. If I built a large machine, I’d probably use a corexy system and make the bed the z axis.
Im thinking about an 18 inch cube
Oh that’s not too bad. I’d definitely go with aluminum extrusion still. Also, the z axis being the bed makes the total build size slightly larger than the bed.
When you get larger you get more flex and slop and less precision. Longer belts stretch proportionally more. More power is needed to move heavier things. Larger heated beds take a lot more power. Small degrees of misalignment become a bigger issue. That’s what I can come up with.
I have a ‘big one’. In fact, it’s the first and only printer I’ve built. And I wouldn’t do it again.
Why? With big printers come heavier smooth rods, ( if you go that way) a much heavier build plate, not only because of the size of the plate, but also because a build plate that big needs a far better heating than possible with standard little pcb heaters.
Think about it, with a build plate almost twice as big, you don’t want to wait 30 minutes or longer to heat up your bed.
All of that extra weight comes with heavy demands on your stepper-motors, drivers, etc. The type of construction you would use on a typical reprap, is not sufficient for large printers.
And most of the time you don’t need all that space, but you do have to heat it all up and move it around all the time.
So definitely keep your small printer for normal jobs.
Currently I am using 3 motors in parallel for the bed, and I’m using big 2,5 to 4 amps stepper drivers to do the job,
Heating the bed is done with 1400 Watt heating elements, regulated with a solid state relay, on mains power.
And for the stepper motors an extra 24VDC power supply.
Currently I’m rebuilding / redesigning the damn thing with hollow rods, plastic bearings, and a lot of other weight-reducing measures.
It’s not all bad. I’ve learned a lot. I’ve had fun. But the times that I almost used a angle-grinder to cut the thing down to a useful size…
And I did have the ‘pleasure’ to use a big portion of the bed. It;s great to be able to print 20 of the same objects in one go. But the time it takes to print those 20 objects grows enormous. And then after 12 hours of printing, a stepper motor decides it’s been fun, and skips a few steps. Angle grinder visions again. That reminds me, that’s another thing that I need to do. Water-cool the stepper motors.
But your mileage may vary.
mmmm… Wire Deltas…
Beyond a certain point deltas scale better due to less weight to move around and all vertical members. Its usually more effective to get two smaller printers and cut the model in half. Twice the productivity.
My biggest printer does 350wx450lx540h its big which i nice i never think oh hope it will fit. My small printer is 20x20x15 small but also fast and acurate. It prints the nasa wrench no problem. If have to say imo ideal size is 30x30x40 it will get 90% of what you need done hight you can drop to 20 and still be fine but every now and then you need to print the eifel tower or whatever and if it needs another 10mm in hight to finnish its annoying. Over 400mm high z stability needs bigger rods and bearings to stay still or much slower printer speed.